Browsing by Author "Mühlig, Christian"
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- ItemAbsolute Absorption Measurements in Optical Coatings by Laser Induced Deflection(Basel : MDPI, 2019) Bublitz, Simon; Mühlig, ChristianAbsolute measurement of residual absorption in optical coatings is steadily becoming more important in thin film characterization, in particular with respect to high power laser applications. A summary is given on the current ability of the laser induced deflection (LID) technique to serve sensitive photo-thermal absorption measurements combined with reliable absolute calibration based on an electrical heater approach. To account for different measurement requirements, several concepts have been derived to accordingly adapt the original LID concept. Experimental results are presented for prominent UV and deep UV laser wavelengths, covering a variety of factors that critically can influence the absorption properties in optical coatings e.g., deposition process, defects and impurities, intense laser irradiation and surface/interface engineering. The experimental findings demonstrate that by combining high sensitivity with absolute calibration, photo-thermal absorption measurements are able to be a valuable supplement for the characterization of optical thin films and coatings.
- ItemLinear and nonlinear absorption of titanium dioxide films produced by plasma ion-assisted electron beam evaporation: Modeling and experiments(Basel : MDPI, 2019) Stenzel, Olaf; Wilbrandt, Steffen; Mühlig, Christian; Schröder, SvenTitanium dioxide films were prepared by plasma ion-assisted electron beam evaporation. Linear optical properties were investigated in terms of spectrophotometry using the beta-distributed oscillator (ss_do) model as a parametrized dispersion law. The nonlinear two-photon absorption coecient of titanium dioxide was determined by means of the laser-induced deflection technique at a wavelength of 800 nm. The obtained values of (2-5) x 10-11 cm/W were consistent with published experimental values for rutile as well as for simulations performed in the frames of the ss_do and Sheik-Bahae models. © 2020 by the authors.